Continuity mistake: Roseanne comes home and the kitchen cabinets are not painted/plain wood. In the very next shot from a different angle, the cabinet doors are painted.
Continuity mistake: After Booker announces the overtime, Roseanne asks Jackie for a quarter. Jackie takes her glove off her right hand. In the next shot, Jackie reaches into her purse and takes her glove off her right hand a second time, before getting a coin out of her coin purse.
Answer: Clearly, the only person who could truly answer this question would be a set designer for the series, or someone else directly connected to the series who would have this kind of detailed information. I looked on IMDb.com and Cheryl Lanner is credited as set designer through 1997. I quickly found her Facebook page, and I directed your question to her. After some time, Ms. Lanner has replied as follows: "I decorated the last season 1/2 but after 9 seasons the sofa just plain got worn out and had to be repaired from 8 years of usage. There was a board put on the sofa but as I've said, it was due to so much usage. If they had back problems I was unaware of them, but you can be assured that if that was the problem it would have been fixed immediately. Take care Michael!"
Michael Albert